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Old June 8, 2012, 04:11 PM
zsayeed zsayeed is offline
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Join Date: April 19, 2007
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Quote:
Originally Posted by ammark
I figured sth like this was up on Wednesday. Was pinging sgix.sg, and wasnt getting any ping response. Ping response from OpenDNS server in US was around 1100ms+.
Interesting, the 1100 msec does seem like a vsat link. The Geostationary orbit is 35786 km; hence the round trip time just from propagation itself would be 2X(35786 km/3e5 km/sec) = 238 m-sec (one way, from you to the gateway); ping is round-trip, so multiply that with two for the reverse link: you->satellite->gateway->satellite->you = 500 m-sec from propagation delay alone. The rest of the 600 or so m-sec sounds like congestion from the FiFos of overloaded switches/routers in between.

Heavy Satellite RTT+Overloaded switches. Plus you should see some dropped packets as well.

PS: In-fact I am getting average 550 m-sec ping time to sgix.sg; that path/server is bad! I don't think I am going over satellite.
Unless, Singapore itself is severed from RoW. Which I doubt.
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Last edited by zsayeed; June 8, 2012 at 10:40 PM..
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